Electronic signal analyzer for a series of successive pulses



Sept. 6, 1966 P. J. DALY ETAL ELECTRONIC SIGNAL ANALYZER FOR A SERIES OF SUCCESSIVE PULSES Filed Feb. 27, 1962 2 Sheets-Sheet 1 d. wNw

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United States Patent O 3,271,678 ELECTRONIC SlGNAL ANALYZER FOR A SERIES OF SUCCESSIVE PULSES Paul J. Daly, Quincy, and Joseph F. Clark, Lexington, Mass., assignors to the United States of America as represented by the Secretary of the Air Force Filed Feb. 27, 1962, Ser. No. 176,159 2 Claims. (Cl. 324-121) The invention described herein may be manufactured and used by or for the United States Government for governmental purposes without payment to us of any royalty thereon.

This invention relates to a system for displaying on a cathode ray oscilloscope a series of pulses and, more particularly, for producing a series of pulses superimposed on a stepped-output signal for display on aforesaid oscilloscope and a camera interconnected with said system to photographically record the stepped display.

During the operation of many electronic systems, there are generated a multiplicity of pulses. It is highly desirable to simultaneously View and permanently record a series of aforesaid pulses so that changes in amplitude, pulsewidth, jitter, etc. could be noted. The comparison of a series of successive pulses achieved thereby provides an invaluable aid in the performance of a transient analysis.

The present invention provides an electronic signal analyzer system for displaying on a cathode lray oscilloscope a series of successive pulses superimposed on a stepped-output signal and `a camera interconnected with aforesaid system to photographically record the series of pulses being analyzed. The series of pulses to be analyzed are applied to a pair of input circuits. The rst of the pair of input circuits provides a time delay for the series of pulses being analyzed. The second input circuit accepts the series of pulses; the rst pulse and each successive pulse of the series triggers the sweep of the cathode ray oscilloscope.

The series of pulses are utilized to generate a steppedoutput signal which is mixed with the delayed series of pulses to produce a signal which is stepped and in which each step has super-imposed thereupon one of the pulses of said series of delayed pulses. An electronic switch is utilized to shut off the second input circuit after the step counter has reached a predetermined number of steps. The irst step of the stepped-output signal actuates a relay thereby operating to open the shutter of the aforesaid camera. After the last step of the stepped signal, the camera shutter is closed as the relay has been deprived of an actuating signal.

An object of the present invention is to provide a novel system for displaying and photographing a series of successive pulses.

Another object of the present invention is to provide a system for viewing simultaneously a series of successive pulses wherein each pulse of said series is utilized to generate a pulse thereby producing a stepped-output signal, the first and last lof the steps actuating a camera.

Still Kanother object of the present invention is to provide a system for Viewing and recording a series of successive pulses simultaneously appearing on the face of 'a cathode ray tube of an oscilloscope wherein the rst of the pulses turns on trigger source for the sweep of aforesaid oscilloscope rand the last of the pulses shuts off the trigger source.

Yet another object of the present invention is to provide a Isystem which displays and photographs simultaneously a series of successive pulses wherein the series of pulses are superimposed upon a stepped-output signal and in which the first and last steps control a camera which is utilized to photograph the display of said superimposed signals.

3,271,673 Patented Sept. 6, 1966 The various features of novelty which characterize this invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages and specic objects obtained with its use, reference should be had to the accompanying drawings and descriptive matter in which is illustrated and described a preferred embodiment of the invention.

Of the drawings:

FIGURE 1 illustrates in block diagram form a preferred embodiment of the invention; and

FIGURE 2 is a schematic diagram of the invention.

Now referring in detail to FIGURE 1, there is shown gated blocking oscillator 3 receiving pulses (as illustrated) by Way yof common input terminal 2. For each input pulse, gated blocking oscillator 3 produces a pulse at its output which is fed through cathode follower 4 to the external synchronization input of cathode ray oscilloscope 14 and simultaneously to step counter 5 and each of the pulses generates a sweep in the cathode ray tube of oscilloscope 14. Step counter 5 produces at point 13 a stepped output, each step representing an individual input pulse into vstep counter 5. From point 13, the stepped output signal is fed to discharge blocking oscillator 8 and simultaneously to mixer 7 by way of cathode follower 6. The amplitude of the bias voltage on discharge blocking oscillator 8 is preselected so that when the stepped output signal applied thereto reaches a predetermined magnitude, discharge blocking oscillator 8 conducts thereby generating a single pulse which is applied to electronic switch 10 by way of cathode follower 9. Electronic switch 10, upon receipt of an input pulse, prevents gated blocking oscillator 3 from conducting which in turn shuts off the trigger source for the oscilloscope sweep and also the pulse source to step counter 5.

It is to be noted that prior to the generation of a pulse from discharge blocking oscillator 8, a stepped output signal has been introduced into lmixer 7, simultaneously the aforementioned mixer has received pulses from cathode follower 12 by Way of delay 11. Delay 11 Ireceives a series of pulses from common input terminal 2. Mixer 7 superimposes a delayed input pulse on each step of the stepped input signal applied thereto. The output signal from mixer 11 is then a stepped output voltage, each step having `superimposed thereupon a delayed pulse. The superimposed signal is applied to the vertical amplier terminal of cathode ray oscilloscope 14.

Oscilloscope camera is arranged to photograph the face of cathode ray oscilloscope 14. Associated with camera 15 is relay 16 which is positioned so that the shutter of camera 15 is normally closed. The steppedoutput signal from mixer 7, Shown at point 17, is fed to relay 16, and the initial step thereof actuates relay 16 to open the shutter of camera 15 and after the last step thereof the voltage goes to zero thus operating to close the shutter of camera 15. There is thus provided `a system whereby a series of pulses are displayed on the face of a cathode ray oscilloscope, each pulse being displaced vertically from the other. The first and last step of the superimposed stepped signal actuates a camera to yautomatically photograph aforesaid series of pulses.

Now referring to FIGURE 2, there is shown a schematic diagram of FIGURE 1 in which common input pulses are applied to terminal 2', the pulses then are fed to gated blocking oscillator 3' which is represented by electron discharge devices 23 and 24 with their associated circuitry. Electronic switch 10 is represented by electron discharge device 25 and associated circuitry. The plate of electron discharge device 25 is initially at +40() Volts. By virtue of this, the voltage divider output from the aforesaid plate `to the gated grid of electron discharge device 24 is above the positive potential needed for gating purposes. Therefore gated blocking oscillator 3 delivers a pulse to cathode follower 4', which includes electron discharge device 26. At point 27, a trigger voltage for cathode ray oscilloscope 14 is derived. The oscilloscope, being connected to external synchronization, receives a trigger and generates a sweep. Step counter represented by electron discharge devices 28 and 29 and associated circuitry also receives aforesaid trigger. During this'period, capacitor 30 which is part of the step counter builds up a charge each time a pulse arrives, and depending upon th'e setting of potentiometer 31, there may be counted a predetermined number of pulses. The setting of potentiometer 31 adjusts the bias voltage for blocking oscillator 8', represented by electron discharge device 32 and associated circuitry. When the charge of capacitor 30 is high enough to overcome the bias voltage 0n electron device 32, the latter conducts, generating a single pulse from the tertiary winding of blocking oscillator 8. This pulse is coupled over to electronic switch by way of cathode follower 9 and electron discharge device 2S conducts. The plate voltage of electron discharge device drops to a very low value. Therefore point 34 is now negative and gated blocking oscillator 3 does not conduct which in turn shuts olf the trigger source to oscilloscope 14' and also the pulse source to step counter 5'.

It is to be noted that prior to the generation of the pulse from blocking oscillator 8', a stepped output signal at point 35 is present. Aforesaid stepped output signal contains a predetermined number of steps. This stepped output signal is introduced to electron discharge device 37 of mixer 7 by Way of cathode follower 6. Mixer 7 is represented by electron dicharge devices 36 and 37 and associated circuitry. Simultaneously electron discharge device 36 of mixer 7 receives pulses by way of cathode follower 12 from delay 11. Delay 11 receives input pulse from terminal 2. Delay 11 is comprised of single pole-three position switch 38 and associated inductors, resistor and capacitors. Switch 38 can connect cathode follower 12 to input terminal 2 by way of position 39, 40, or 41 thus providing three diierent delays for the input pulse received by way of terminal 2.

The delayed pulses are fed into electron discharge device 36 and simultaneously a stepped signal is applied to electron discharge device 37 of mixer 7. The output signal from mixer 7 is comprised of a stepped output signal, each of the steps having superimposed thereupon a pulse. The stepped pulse with superimposed pulses is displayed on cathode ray oscilloscope 14 and is photograph'ed as hereinbefore described in the detailed operation of FIGURE 1.

While, in accordance with the provisions of the statutes, we have illustrated and described the best; forms of the invention now known to us, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit of the invention as set forth in the appended claims, and that in some cases certain features of the invention may sometimes be used to advantage without a corresponding use of other features.

Having now described our invention, what we claim as new and desire to secure by Letters Patent, is as follows:

1. An electronic signal analyzer, in combination with a cathode ray oscilloscope and a camera, comprising means to generate a successively stepped signal from a series of pulses, each step being representative of a single pulse of said series, means to trigger the sweep of said cathode ray oscilloscope with each pulse of said series of pulses, means to switch olf said triggering means, said switching means being controlled by the last step of said stepped signal, means to delay each pulse of said series of pulses, means to superimpose each of said delay pulses upon the step of said stepped signal representative thereof, and means to display said superimposed signal on said cathode ray oscilloscope.

2. An electronic signal analyzer for a series of successive pulses comprising a gated blocking oscillator and delay means simultaneously receiving `a series of successive input pulses, said gated blocking oscillator providing an output pulse for each of said input pulses, cathode ray oscilloscope means having an external synchronization input terminal receiving said output pulse by way of `a cathode follower, each of said output pulses triggering a sweep in said cathode ray oscilloscope means, a step counter also receiving the output signal pulse from said cathode follower, said step counter providing la stepped output signal, each step being representative of each of said successive pulses of said series of pulses, a discharge blocking oscillator receiving said stepped output signal, said discharge blocking oscillator conducting upon said stepped output signal attaining a predetermined magnitude and generating a single output pulse for each stepped output signal, an electronic switch receiving said single output pulse, said electronic switch operating to gate olf said gated blocking oscillator upon receipt of said single output pulse, and a mixer simultaneously receiving said stepped output signal and a delayed seri'es of successive input pulses, said mixer superimposing a delayed input pulse on each step of the stepped input signal received thereby, said mixer output signal being received 4at the vertical amplifier terminal of said cathode ray oscilloscope means.

References Cited by the Examiner UNITED STATES PATENTS 2,595,646 5/1952 Doba et al. 324-57 2,881,388 4/1959 Behrend 324-77 X 2,906,584 9/1959 Hammer et al 346--110 2,906,947 9/1959 Dischert et al 324-57 2,965,434 12/1960 Downs 326-110 3,021,479 2/1962 Di Toro et al 324-77 3,054,053 9/1962 Cook 324-77 FOREIGN PATENTS 722,205 1/ 1955 Great Britain.

OTHER REFERENCES Radio-Electronics: December 1955, Rainbow Patterns with Conventional Generators, p. 96.

WALTER L. CARLSON, Primary Examiner.

LEO SMILOW, Examiner.

N. I. AQUILINO, A. E. RICHMOND,

Assistant Examiners. 

1. AN ELECTRONIC SIGNAL ANALYZER, IN COMBINATION WITH A CATHODE RAY OSCILLOSCOPE AND A CAMERA, COMPRISING MEANS TO GENERATE A SUCCESSIVELY STEPPED SIGNAL FROM A SERIES OF PULSES, EACH STEP BEING REPRESENTATIVE OF A SINGLE PULSE OF SAID SERIES, MEANS TO TRIGGER THE SWEEP OF SAID CATHODE RAY OSCILLOSCOPE WITH EACH PULSE OF SAID SERIES OF PULSES. MEANS TO SWITCH OFF SAID TRIGGERING MEANS, SAID SWITCHING MEANS BEING CONTROLLED BY THE LAST STEP OF SAID STEPPED 